Update .gitignore file.

Author: azurechen

.gitignore

@@ -4,7 +4,7 @@
 
 ## Build generated
 build/
-DerivedData
+DerivedData/
 
 ## Various settings
 *.pbxuser
@@ -15,23 +15,32 @@ DerivedData
 !default.mode2v3
 *.perspectivev3
 !default.perspectivev3
-xcuserdata
+xcuserdata/
 
 ## Other
-*.xccheckout
 *.moved-aside
-*.xcuserstate
+*.xccheckout
 *.xcscmblueprint
 
 ## Obj-C/Swift specific
 *.hmap
 *.ipa
 
+## Playgrounds
+timeline.xctimeline
+playground.xcworkspace
+
+# Swift Package Manager
+#
+# Add this line if you want to avoid checking in source code from Swift Package Manager dependencies.
+# Packages/
+.build/
+
 # CocoaPods
 #
 # We recommend against adding the Pods directory to your .gitignore. However
 # you should judge for yourself, the pros and cons are mentioned at:
-# http://guides.cocoapods.org/using/using-cocoapods.html#should-i-ignore-the-pods-directory-in-source-control
+# https://guides.cocoapods.org/using/using-cocoapods.html#should-i-check-the-pods-directory-into-source-control
 #
 # Pods/
 
@@ -41,3 +50,13 @@ xcuserdata
 # Carthage/Checkouts
 
 Carthage/Build
+
+# fastlane
+#
+# It is recommended to not store the screenshots in the git repo. Instead, use fastlane to re-generate the 
+# screenshots whenever they are needed.
+# For more information about the recommended setup visit:
+# https://github.com/fastlane/fastlane/blob/master/docs/Gitignore.md
+
+fastlane/report.xml
+fastlane/screenshots